There are numerous instances where hydrocarbon fuels become mixed with water following leakage from tanks, spills of fuels on the ground and from condensation of moisture within a tank as may occur when the fuel tank is substantially empty.
Modern gasolines are being formulated with increasing amounts of organic oxygenates, such as methyl tertiary butyl ether (mtbe), methyl tertiary amyl ether (tame), and the like. The oxygenates are more soluble in the water than are the traditional hydrocarbon components of the fuels. When water becomes contaminated with minor amounts of these organics it is desirable to remove the organic content so as to negate environmental problems. The greater affinity of the oxygenates for water leads to generally higher concentrations of the oxygenates in water than has historically been found for hydrocarbons and renders separating them from the water to increasingly lower levels mandated by regulations a difficult problem.
A traditional way for treating wastewater contaminated with volatile organics, then, is to contact the wastewater in a stripping column with a gas such as air, as disclosed e.g. in British Patent 2,035,814A. When designing the equipment for a given set of conditions the amount of contaminant that can be removed decreases as the temperature decreases.
When groundwater becomes contaminated with minor amounts of these organics, vast amounts of energy may be required to reduce the organics to a level of less than a few parts per million, and even more energy to achieve levels in the parts per billion range.
It is an object of this invention to provide an energy efficient system having the capability for continuous operation to treat significant quantities of e.g. contaminated groundwater, and to reduce the contamination by oxygenates to environmentally acceptable levels.
It is a further object to dispose of the removed oxygenates in an energy efficient as well as environmentally acceptable matter.